Microbiological assessment of surfaces

Abstract
Summary: The main methods in use in laboratories for the microbiological assessment of surfaces are examined, viz. (1) the swab‐rinse, (2) the rinse, (3) the agar contact, and (4) the direct surface agar plating. The advantages and disadvantages of these are discussed and their suitability for particular purposes in the food industry. Methods employed in the author's laboratory are discussed for sampling surfaces in milk plants, farm dairies, canneries, meat and poultry processing plants. Consideration is given based on actual investigations of the use and limitations of the swab‐rinse technique and its variations and the rinse and the agar sausage techniques. The importance of careful interpretation of and use of the results is stressed. Microbiological standards are suggested for cleaned surfaces, working surfaces in meat and poultry processing plants and for cattle, sheep and poultry carcases.